Draft control device



April 1961 R. w. FRANKS DRAFT CONTROL DEVICE Filed 001;. '7, 1957 x will! I 'IIII/A IN V EN TOR.

U t d Se i a 1 2,978,184 1 DRAFT coNTRoL DEVICE Roye W. Franks, 1300 Lakeshore Drive,

Michigan City, Ind.

Filed Oct. 7, 1957, Ser. No. 688,744

The invention "relates generally to equipment for heating apparatus andmore particularly is directed to a draft controldevice for such apparatus.

The primary object of the invention is to provide a draft control device embodying improved principles of design and 1 construction.

An important object of the invention is to provide a control device which can be easily and quickly installed in a pipe or flue between a heating unit and a chimney.

A significant object of the invention is to provide a unique structure which includes a housing and a detachable cover or shell therefor, with a vane pivotally mounted on the cover. Otherwise expressed, the structure is comprised of a pair of complementary shell members which can be readily detachably connected together in different operative positions, with the vane movably supported on one of the members.

An object of the invention is to provide novel means for pivotally connecting the vaneto the cover or member so that for every practical installation desired the vane will continue to function as intended.

A particular object of the invention is to provide a control device in which the vane is provided with a novel regulator which comprises a weight and a shaft or shank extending from the weight for supporting the regulator on the vane. The regulator is so constructed that it can be readily reversibly and/ or longitudinally adjusted with respect to the vane for different installations of the control. 7 Another important object of the invention is to provide a vane with a pair of angularly disposed portions and means whereby the regulator can be readily mounted for adjustment on either of the vane portions. The arrangement is such that when attached to one of the vane portions the overall size of the control is reduced so that it may be installed in a smaller space.

Other objects and advantages of the invention reside in its simplicity of design and construction, durability, efliciency under all operating conditions, and economy in manufacture and assembly.

Additional objects of the invention will become apparent after the description hereinafter set forth is considered in conjunction with the drawings annexed hereto.

Referring to the drawing, wherein a preferred construction of the invention is exemplified:

Figure 1 is a perspective view showing the control structure, embodying the invention, arranged in a horizontal flue or pipe;

Figure 2 is a side view in elevation of the control device, with portions thereof in section, to illustrate the manner of mounting the vane;

Figure 3 is a top view of thecover shell;

Figure 4 is a partial bottom view of the control device looking in the direction of the arrows 4--4 in Figure 2;

Figure 5 is a partial section showing the components of a snap connection means employed to connect the shell membe'rstogether;

Patented Apr. 4, 1961 Figure 6 is a partial perspective view of one of the components of the snap connection means;

Figure 7 is a partial perspective view of the vane showing the manner of mounting and guiding the regulator thereon; and Y Figure 8 is a partial bottom view of the cover shell illustrating structural details.

Considering the drawings more in detail and referring first to Figure 1, the structure includes, among other things, a housing or shell member generally designated 1 which is adapted for direct support on a horizontal flue or pipe 2, acover or shell member 3 detachably connected to the housing 1, an angular vane 4 pivotally mounted on the cover, and a regulator 5 carried by and adjustable on the vane.

The housing or shell 1 may be designed and constructed in various ways but as exemplified in Figure 1, preferably includes a pair of upper and lower corresponding planar parallel walls, and a pair of corresponding planar parallel end walls provided with tubular extensions 6 for telescoping connection with sections of the flue 2 to place the housing in a substantially horizontal position forsupporting the shell or cover 3. Obviously, the housing 1 and shell 3 can be mounted in a vertical flue or in any desirable inclined position.

"The walls of the housing 1 preferably form a square, with the free marginal edges of the walls arranged in the same plane. Each of these walls, substantially midway its marginal edge, is preferably provided with an opening 7 as depicted in Figure 5 and constitutes a component of a means for detachably locking the cover and housing together.

' The cover shell 3 may be formed in various ways but as illustrated in'Figures 1, 2 and 3, embodies improved principles of design and construction, and, among other things, includes a top wall 8, a bottom wall or member 9 parallel to the top wall, and corresponding parallel end walls '10 of trapezoidal shape. The top wall is substantially rectangular in shape and provided with a forwardly extending continuation or upper inclined front wall 11 having flanges 12 which are secured in exterior overlapping relation to the end walls 10 in a desirable way, such as by welds 13. The top, end and inclined walls are preferably constructed in one piece and formed as shown whereas the bottom Wall 9 is preferably a separate member having its ends secured between the the ends of the bottom wall member 9 and inclined portion 15 thereof as evidenced in Figure 8. The shell also includes What may be termed an inclined lower front wall which is preferably formed by providing the end walls 10 with inturned relatively narrow portions 18 having rearwardly extending flanges 19' disposed in spaced parallel relationship to the end walls. The end walls are also provided with similar narrow inturned portions 20 having rearwardly extending flanges 21 adjacent the upper inclined Wall 11. The inclined portion 15 of the 1 bottom wall and the narrow inturned portions 18 formrelatively narrow inturned portions 20 of the end walls,

which in effect constitute continuations of the wall 11,

23 of the vane 4 in a manner which will be described more in detail subsequently. Otherwise expressed, the cover shell is provided with a pair ofconverging inclined front walls provided with intersectingopenings defining a larger opening. r

It is to be understood that the use of such terms as end walls, side walls, top wall, bottom wall and inclined walls are merely relative expressions and are not to be construed as limiting the scope of the invention.

The top, bottom and end walls of the cover shell 3 form a square which is substantially the same size as the square formed by the walls of the housing 1. It is to be understood that the housing and shell may be constructed in other shapes and that any suitable means may be provided for detachably securing them together. One form of a detachable connection comprises providing the free marginal edge portion of each of the walls of the cover shell with a pair of longitudinal offsets 24- for slidably embracing the free marginal edge portions of the walls of the housing 1 as illustrated in Figures 5 and 6. Midway between the longitudinal offsets 24 on each of the walls just referred to, there is provided a yieldable or resilient portion 25 having a projection 26 thereon for detachably locking the housing and cover shells together.

It will be noted that longitudinal offsets 24 form shoulders or stops 27 which limit inward telescoping movement of the shells and that when the shells are assembled, the projections 26 on the yieldable portions 25 will fit in the openings 7. The projections are preferably curved as shown so that the portions of the housing disposed between the offsets 24 will be gradually cammed downwardly until the edges of the housing walls more or less engage the shoulders 27 on the cover shell, whereupon the projections will snap into the openings to obtain four individual positive locks. The projections or openings may be termed abutment means or locking components, and, if desired, these components may be reversed so that the openings are in the yieldable portions 15 and the projections are on the marginal edge portions of the housing. The cover shell 3 can be readily removed from the housing 1 by merely pressing inwardly on the projections to release them from the openings. Obviously, other forms or types of locking means may be employed but the one exemplified has proven very satisfactory and eflicient muse.

The vane structure and mode of mounting it on the cover shell will now be described. The vane includes the angular portions 22 and 23-, above referred to, which are preferably arranged at an acute angle substantially corresponding to the angular relationship of the openings in the shell to open and close the same. The larger and lower vane portion 23 is preferably provided with side flanges 28 and a bottom flange 29 for disposition substantially within the confines of the flanges 16 and 19 and the upper portion 22 of the vane has side flanges 30 for disposition between the flanges 21 on the side walls when the vane is in a closed position. The upper portion of the vane is also of a size to overlap the lower marginal edge of the upper inclined front wall 11 so as to limit or predetermine the closed position of the vane. In other words, the inclined wall 11 serves as a stop for limiting movement of the vane in a counter-clockwise direction as viewed in Figure 2.

The vane can be operatively mounted on the cover in any desired manner but as shown is preferably pivotally connected thereto by providing the vane with a pair of correspondingpintles 31 and the cover shell with a pair of corresponding fittings 32 having sockets 33- which receive the pintles. The pintles or shafts are preferably anchored to the vane adjacent the junction between its portions 22 and 23- in a conventional manner so that portions of the pintles project laterally from the vane. The fittings 3-2 are preferably constructed from nylon to promote efficiency and detachably secured against the inner surfaces of the flanges 20 and side walls 10 by screws 34 which extend through the flanges and into free to pivot relative to the openings in response to fluid v pressures.

As stated above, one important feature of the invention resides in providing a novel regulator which can be readily adjusted to compensate for differences in vertical and horizontal installations and in other angular installations. The regulator 5 is unique in character and as clearly shown in Figures 1, 2, 4 and 7 is preferably comprised of a single strip of metal which is formed to provide a coil constituting a weight 35 which is offset with respect to a shaft or flat shank portion 36 having a longitudinal slot 37 therein. The shank may be provided with suitable indicia to indicate the location the regulator should take when the complete control device is installed in a horizontal or near horizontal flue 2, as shown in Figure l, and when installed in a substantially vertical or other angular operative position.

As alluded to above, one of the objects of the invention is to provide :a setup whereby the regulator can be readily attached to either portion of the vane. The means employed for securing the regulator in the desired position on the larger vane portion 23 includes a threaded stud 38 and a knurled nut 39. The inner end of the stud is anchored to the vane portion 23 by any suitable means and its outer end extends through the slot 37 in the shank. Longitudinal movement of the regulator is preferably accomplished by a pair of aligned ribs 40 formed in the vane on either side of the stud and which project into the slot as shown in Figure 7. The opposite sides of the shank of the regulator are also provided with calibrations or line graduations which are adapted for selective registry with the axis of the stud 38. The calibrations have been predetermined so that a person installing the control can readily adjust the control to the draft required by any furnace or stove without the use of a separate draft gauge. It is to be understood that if found desirable, the calibrations may be placed on the vane in lieu of on the regulator. The regulator is calibrated for all required water column inches and when the draft for a manufacturers furnace is given, it is a simple matter to adjust the regulator in accord with any known draft requirement and then look it in place.

The regulator is connectible to the smaller vane portion 22 by providing this portion with a threaded stud 41 and ribs 42 for receiving the slot 37 in the regulator and the nut 39 can be used to lock the regulator in any desired position on the vane portion 22. With this unique setup the regulator can be readily attached to either of the vane portions. the smaller vane portion the overall size of the control is reduced and this allows one to install the control in a smaller space.

Attention is directed to the fact that utilizing an angular vane of the kind described produces a more effective area exposed to the pressure differential which is the motivating influence on the vane. Since the angled areas are exposed to this prwsure differential, the vane will respond more quickly to smaller draft fluctuations. Also, the rotative angle is decreased by forming and mounting the vane as described. If the vane hangs substantially vertically, it must rotate through degrees to open fully. It is relatively simple to balance the vane correctly through this smaller are or range of movement. Furthermore, since there is very little friction at the pintles When the regulator is mounted on or pivots, the vane is made sensitive to any slight change in the pressure differential.

In View of the foregoing, it be manifest that the control device embodies improved principles of design and construction which in use have proven of great value in maintaining proper combustion of fuel.

Having thus described my invention, it is obvious that various modifications may be made in the same without departing from the spirit of the invention, and, therefore, I do not wish to be understood as limiting myself to the exact form, construction, arrangement, and combination of parts herein shown and described.

I claim:

1. A control of the kind described comprising a shell having a pair of trapezoidal side walls joined together by top and bottom walls and a pair of inclined converging front walls provided with a large opening and a smaller opening disposed in planes intersecting one another at an acute angle, and a vane pivotally mounted on the shell adjacent the intersection of said planes and having large and smaller portions for respectively opening and closing the large and smaller openings in response to fluid pressure.

2. In a draft control device comprising an open ended shell for passage of fluid therethrough from the open end thereof into a flue or the like, a unitary vane adapted to be opened by excess pressure on the outer side thereof,

means on said shell and on said vane for pivotally mounting the vane for movement about an axis transverse to the longitudinal axis of the shell, said vane having dilferent portions on opposite sides of said axis and disposed at an acute angle relative to each other about said axis for increasing the effective area of the vane to motivating pressure, the relationship of said portions to the shell being such that when the vane is disposed in one position the outer peripheries of said portions are disposed adjacent said shell to close and prevent flow of a fluid through the shell, and when moved about said axis from the closed position toward open position the peripheries of said portions respectively move progressively toward the center of said shell and directly away from the shell whereby restriction of fluid flow past each of said portions progressively diminishes as said vane is pivotally moved from closed position toward full open position.

References Cited in the file of this patent UNITED STATES PATENTS 1,292,132 Stoltenberg I an. 21, 1919 1,971,336 Butler Aug. 28, 1934 2,179,940 Lawson Nov. 14, 1939 2,276,728 Johnson et al Mar. 17,= 1942 2,522,786 Hubbart Sept. 19, 1950' 2,808,992 Franks Oct. 8, 1957 

